Intestinal Absorption Of D-galactose Research Articles

Effects of trecadrine, a beta 3-adrenergic agonist, on intestinal absorption of D-galactose and disaccharidase activities in three physiopathological models.

Impairments in intestinal absorptive and digestive processes have been described in several pathophysiological situations, such as in drug-induced diabetes, obesity and hypercholesterolaemia. Furthermore, there is evidence for the occurrence of beta 3-adrenoceptors in multiple regions of the gastrointestinal tract, but there are no data concerning their possible involvement on jejunal and ileal digestive and absorptive functions. In this work, we have measured the modifications of selective intestinal absorption and disaccharidase activities in alloxan-induced diabetic and in diet-induced obese and hypercholesterolaemic Wistar rats. The action of a beta 3-adrenergic agonist (Trecadrine) with hypoglycaemic and lipolytic properties on those gastrointestinal functions has been studied. Increases in the galactose uptake by intestinal rings and in both sucrase and maltase activities were found in diabetic rats. The results obtained after Trecadrine administration to diabetic rats led to an improvement of the altered values. On the other hand, our data show a decrease in sugar absorption and in disaccharidase activities in both obese and hypercholesterolaemic groups, probably related to the low carbohydrate and high fat content of these diets. An amelioration in sucrase activity was observed after treatment with Trecadrine. Finally, Trecadrine administration to control animals significantly inhibited galactose intestinal absorption, which was independently confirmed by additional in-vitro studies. Overall, these results could be attributed not only to an improvement in the pathophysiological condition (diabetes, obesity and hypercholesterolaemia), but also to a direct effect of the beta 3-adrenergic agonist on the intestinal absorption processes.

Calcium-cadmium interaction on sugar absorption across the rabbit jejunum.

The element Cd is considered to have no biological function and is highly toxic to humans and animals. Toxic effects of this metal upon cell membrane structure and function have been shown. On the other hand, Ca is an essential element in a wide variety of cellular activities. The present study was initiated to research whether the interaction between Ca and Cd could affect D-galactose absorption across the rabbit jejunum in vitro. In media with Ca2+, when CdCl2 was present at 0.5 or 1 mM, Cd was found to significantly reduce the sugar absorption. In Ca2+ -free media, where CaCl2, was omitted and replaced isotonically with choline chloride, the sugar transport was not modified by Cd, but when CaCl2 was replaced isotonically with MgCl2, the inhibition is observed. Verapamil at 10(-6)M (blocking mainly Ca2+ transport) did not modify the inhibitory effect of cadmium on D-galactose transport. When 10(-6)M of A 23187 (Ca2+ specific ionophore) was added in media with/without Ca2+; CdCl2 produced no change in D-galactose transport. These results suggest that Ca and Cd could have affinity for the same chemical groups of enterocyte membrane, which would be related with the intestinal absorption of D-galactose.

Intestinal absorption of D-galactose in the presence of extracts from Phaseolus vulgaris hulls.

The relatively low nutritional value of protein from legume seeds has been attributed to the occurrence of some antinutritional factors and the poor content in sulphur aminoacids, which leads to undesirable physiological and biochemical alterations. However, the intimate nature of these processes remains unclear. In order to evaluate the influence of naturally occurring substances of legume constituents on nutrient utilization, the intestinal absorption of D-galactose in the presence of aqueous or alcoholic extracts, obtained from Phaseolus vulgaris hulls, has been measured by use of the in vivo successive absorption technique. Aqueous extracts inhibited significantly (p less than 0.01) the uptake of D-galactose at different times of exposure, while no changes in sugar transport were observed with the alcoholic solutions. Polyamide treatment (a polyphenolic complexing agent) of the aqueous extracts decreased its ability to inhibit sugar uptake. Kinetic studies showed that the aqueous fractions modify Vmax values for D-galactose absorption and also KT data. This inhibition appeared to be reversible after short periods of exposure, affecting mainly the active component of transport. Therefore, it can be suggested that some substances, contained in aqueous extracts of Phaseolus vulgaris reduce sugar absorption. Furthermore, our studies seem to indicate that polyphenols are, at least partly, involved in this phenomenon.

Growth rate, muscle protein composition, intestinal absorption of D-galactose and L-leucine and nitrogen balance in rats fed the raw legume Chamaecytisus proliferus L.

Growth rate, nitrogen balance, skeletal muscle nitrogen fractions and in vivo intestinal absorption of D-galactose (2 mM) and L-leucine (20 mM) have been measured in male growing rats (90-100 g initial body weight) fed 12% protein diets containing either casein (control) or the raw leafy legume Chamaecytisus proliferus L. (Western Canary Islands). As compared to control casein-fed rats, those fed the raw legume diet exhibited a significant reduction (P less than 0.01) in the rate of growth, nitrogen balance parameters, sarcoplasmic nitrogenous fraction of skeletal musculature and in vivo intestinal absorption of galactose and leucine; however, the non-protein nitrogenous fraction has been found significantly higher (P less than 0.01) than that of control animals, whereas the myofibrillar nitrogenous fraction remained unchanged. The possible nature of these findings is discussed.

Action of dibenzofurans and naphthalenes on intestinal solute transport and fluid transfer in mice

1. Investigations were made on the effects of a single, oral dose of purified chlorinated dibenzofuran and non-chlorinated dibenzofuran and polychlorinated naphthalenes on in vitro absorption of various solutes and concomitant fluid transfer in the mouse everted small intestine. 2. Absorption of d-glucose decreased 7 days after treatment with each of these chemicals, as did the final d-glucose content of tissue homogenates. d-glucose absorption following membrane hydrolysis of d-maltose was unaltered. d-glucose malabsorption was abolished by an exogenous energy supply ( d-mannose). Intestinal absorption of d-galactose and several amino acids was unchanged. Fluid transfer remained unaltered with each of the solutes. 3. Lowered d-glucose absorption in the experimental animals probably resulted from increased intracellular metabolic effects following absorption and not from impaired function of the d-glucose carrier at the brush border membrane. 4. The apparent malabsorptive effects of d-glucose was both time-dependent and dose-dependent. Dibenzofurans were effective at considerably lower doses compared with naphthalenes. 5. Apparent malabsorption was unrelated to the chlorine content of the chemicals. 6. Histological changes of the small intestine were small and inconsistent; the fresh intestinal weight remained unchanged. 7. The apparent malabsorptive effects of d-glucose using commercial polychlorinated biphenyls and polychlorinated terphenyls were probably caused by traces of toxic chemicals. particularly dibenzofuran, in these compounds.

Small intestinal absorption of D-galactose and water in fasted and alloxan diabetic rats.

Leerdarm- und Krummdarm-Aufsaugung vond-Galaktose und Wasser wurde mit einer Pumpendurchströmung in vivo bei normalen und Alloxan-diabetischen Ratten geprüft. 24 Stunden Fasten erhöhte die Aufnahmefähigkeit normaler Ratten, ergab aber keinen Unterschied zwischen normalen Ratten beim Fasten und solchen, die mit Alloxan für 24, 48 und 72 Stunden diabetisch wurden.